a) Field of the Invention
The present invention relates to a reinforced structural composite consisting of fibers in a polymer matrix; and, in particular, to a responsive, externally-activated two phase material consisting of pre-stressed continuous fibers, restrained and controlled by a discontinuous fiber reinforced polymer matrix, wherein both matrix and matrix reinforcing relax at and above a specified temperature.
For the purpose of the current invention the term "fiber" is defined to mean a slender and greatly elongated shape from natural and synthetic material which has tensile strength and comprises fiber, thread, fiber bundles, tow, and filament bundles.
b) Description of the Prior Art
Since the advent of high-strength fibers and their incorporation into polymer composites, the focus within the prior art has been on the structural ability of composites to resist external forces. A multitude of fibers, fiber arrangements, and polymer matrix compositions has been utilized for structural composites. Structural composites are inert materials resisting loads. The present invention concerns a polymer composite that generates force as well as resists force.
In the polymer composite prior art Bettinger, U.S. Pat. No. 5,552,197, discloses dynamic polymer composites which generate delayed dimensional change and force due to pre-stressed fibers constrained and controlled within and by a responsive polymer matrix whereby the response is self-activated time-dependent. Bettinger is limited by the strength of a non-reinforced matrix and the transverse strength of a matrix reinforced by longitudinal fibers. Bettinger is a cylindrical mechanism not a material. The compressive force of Bettinger is limited.